Firstly it's important to note that contrary to its advertising and the game's intro, Breach & Clear is not a simulation. The game has more in common with call of duty scenarios than real life counter terrorism operations. Soldiers acquire perks for a start and weapons are only effective to a fraction of the range of their real life counter parts. It would also be hard to argue that the soldier classes bear much in common with real life soldier roles instead displaying strange attributes like the intelligence specialist's ability to disappear.
The combat itself is fast paced and interesting. It doesn't often feel cheap except when your squad isn't leveled enough to tackle a map. There aren't any game breaking flaws with the combat system such which is more than most tactical level turn based combat games can boost. The game offers incentives to use fire and movement realistically and the ability to flank and suppress means the player has to keep their team on the move. Perma death thankfully can be enabled which gives a lot more weight to the player's decisions. The game uses a WEGO system for the turns but you'll hardly notice because the AI doesn't move around much.
Enemy classes don't offer huge variation but they do provide enough to allow the designers to create some interesting tactical puzzles. Heavily armoured soldiers can cause your team serious trouble if they can close with them and snipers obviously operate at the other end of the spectrum.
The graphics are quite nice with your soldiers displaying the weapons and gear you issued them with. Everything is clear and easy to interpret except some more obvious fog of war would be nice so players would be provided with some idea of which areas had been cleared. The spotting system is balls, soldiers can see through walls and some items completely negate the fog of war completely. This game certainly could have taken a few lessons from the original Xcom in that department.
The level design is often pretty good but the game's original platform holds it back. Maps are too small and quite clearly were designed with short playtimes in mind. They get better as the game goes on but it feels a bit strange that multi story buildings are absent and the game's attempts to emulate this by making assaults on large buildings take up multiple missions doesn't really feel convincing. The game modes provided are Terrorist hunt, bomb diffusal and escape which are all pretty much self explanatory. They all change up the maps slightly but in the long term aren't enough to keep things going stale. Bomb diffusal maps feature the ever annoying enemy reinforcement spawns that are the bane of several srpgs but within the context of this game they work extremely well and give the mode a bit more tension.
The game tries to keep the player's interest by offering what seems at first to be extensive customization options, but realistically half the weapons and gear offered aren't ever really going to come in useful. The outfitting screen could also do with some work as no indication is given how prospective weapon and gear purchases differ from what is already equipped(unless you click back through some menus). Unequipping all the modifications off a weapon can be quite tedious as well.
Besides tactical combat, the game doesn't offer much else and what's there feels somewhat lacking. The potential of the system is never fully explored because the maps never really get that big and the squad size stays at four men. Insertion methods never change with rappling and helicopter assaults never making an appearance. This lack of variation results in the game getting a bit stale after a while.
It can feel a bit half ♥♥♥♥♥ at times too with some design choices(no ability to use smoke is the most glaring one)leading to the player's units taking unavoidable damage in some situations.
That said fire and movement in the title generally works well and dumb tactics are often punished. The market isn't exactly swimming in squad level turn based strategy games so this is a welcome addition.