Those reviews that call this game addicting are right on the money. Those that state it is challenging are also right. I've played 7 campaigns so far and have lost all but 1.
There are many, many frustrating elements to this game. It demands heavy micro-management of your aircraft. For a game whose central theme is air combat, air combat is pretty clumsy. Your pilots will be slaughtered mercilessly by the Luftwaffe's BF-109s. In a one-on-one fight, your AI pilots will fly around in circles chasing a 109, spraying bullets at empty sky until their guns go dry or you break the endless loop. If you break the loop, your pilot will be immediately shot down. You can take the short route and auto-resolve air battles, but if you do so then 100% of your lost pilots will be KIA - that's right, they won't think to bail out unless you tell them. Managing your fighters in combat vs bombers and Ju-87s is usually doable, but against the nimble Bf-109s it's just impossible because the scale is too small and the means of control too clumsy. Against the 109s I will auto-resolve...but this usually results in the loss of 75% of that squadron's pilots due to the aforementioned inability to bail out. Historically, the RAF didn't do this badly vs German fighters.
Speaking of those 109s again...the designers do not seem aware of the severe range restrictions on German fighters during this era. They had no drop tanks, and generally had only about 20 minutes loiter time around London. I am seeing Bf-109s roaming over Lincoln and northern Wales...unless they had an aircraft carrier (they didn't) all those 109s would crash before they made it home.
You are also limited to only 8 aircraft of your own per air battle. No Big Wings with multiple squadrons intercepting the German mass raids - coordinated attacks are impossible. The Germans have no such limitations, so when the Luftwaffe sends 16+ twin engine bombers and 8+ fighters, you must attack them piecemeal with two or three of your (hopefully) 8 plane squadrons. Expect the first two squadrons to be wiped out due to fighting outnumbered, and because the German Bf-109s will kill 2 or 3 of your fighters for each that they lose. In fact, the numerical disparity gives the Germans such an advantage that an 8 Spitfire RAF squadron attacking 16 German Bombers escorted by 12 Bf-109s, is likely to be wiped out without killing a single German aircraft. This has happened repeatedly. You might even win against this raid, but it won't matter because another one is coming loooooong before you can train and rebuild the lost squadrons. If you avoid battle, then they will blast your airfield to bits and you'll lose the planes because they can't land anywhere.
I like the strategic management aspect of building and placing airfields, radar, AA guns etc. However you only get to start with one factory, 1-2 airfields, and ZERO radar stations and AA guns. I would have liked to have seen a little more inventory at the start of the game. Playing a game about the Battle of Britain, where the RAF starts with no radar is a little silly. Radar was a cornerstone of the British air defense network. Southern England was laden with AA guns and barrage balloons, but you don't have them. New airfields, AA guns, and radar are crazy expensive, and your economy builds very slowly. You have the option to choose between Hurricanes and Spitfires in production, but I cannot discern any difference or advantage of one over the other. In this battle of attrition, the Germans will simply out-resource you in 4-5 days.
Squadrons won't land at an airfield if it is "full". So let's say you have two squadrons based at 2 airfields. One squadron was in combat and lost a few planes, with a pilot or two bailing out safely. The remaining aircraft return to base. At the same time your second squadron is also airborne, and the pilots who bailed out from the OTHER squadron start returning to your SECOND squadron's airfield. Now when squadron 2 returns to land, they CAN'T, because squadron 1's bailed out pilots have gone to squadron 2's base, and it is now too full to land at. That means you lose ALL of squadron 2's planes and pilots because they run out of fuel and crash, because two or three pilots WITH NO PLANES are apparently occupying the entire runway!
I fully realise that a simulation of the Battle of Britain should be nail-biting, edge-of-your-seat tense, and certainly not a "milk run." But this game goes a bit too far, to the point where it's almost mathematically impossible to win.
The game menu, instructions, and all written material are rife with spelling and grammatical errors. For example, your daily commander's review may state "We are loosing this battle." "Restart the campagin." Due to the prevalence of Czech and Polish squadrons in the game, I assume that the game was developed in Poland or the Czech Republic by people who did not speak English as their native tongue. If not, WTH? Have someone proofread your material!
Despite all the above criticisms, I am giving the game a thumbs up, because it IS an addictive game that keeps me coming back. But it's also frustrating as hell, and I may not come back much longer. I definitely hope some updates and patches are coming...