To start: I used to add a header to these reviews, but since it often times made the reviews a bit too long, I've left it on my Backloggery page. Even though I don't think that'll be an issue for this game, I feel compelled to point that out anyways. Besides, it's worked fine so far.
Gameplay: If you've never played a DOS-style shooter before, think something like the original Contra but with more maze-y levels. If you have played a DOS-style shooter, this is pretty much par for the course. The stages are labyrinthean with plenty of secrets; some of which are pretty easy to spot while others require you to dig deeper into the level for something like a switch that activates something at the beginning of the level. I got an average of 95% of the points for each of the levels, with the exception of the boss levels, but that's just because of how the game scores points. There's four episodes which consist of five levels a piece; four stages and a boss stage. Hidden somewhere in the first four stages of each episode are items called cells which allow you to get some extra powerups before the boss of that stage. They're not essential, but they certainly do help.
Bosses in this game are actually really good; certainly a lot better than some of the bosses you'd see in the Commander Keen series. I only played through the game on Normal, but even on that difficulty they were a bit of a handful. The final boss was just plain excellent and a great way to end the game. As for the weapons, you have your standard pea shooter, a rapid shot, a five-way spread, a laser that splits and bounces off of walls, a homing explosive shot, and Chaos which just does things and kills enemies sometimes.
Apart from that, that's pretty much your lot for this game. It took me just over an hour and a half to beat the game on normal with a fair bit of exploration of the stages, but that's a pretty good length for a DOS-style game. It definitely has replay value, especially with higher difficulties and 100% playthroughs, so if you're into that kind of thing, this game will certainly be worth the $4. It's simple and compact, and there really isn't a thing Id change about it. 10/10.
Story: Unlike a lot of DOS-shooters, this game actually has a pretty good story. It's a bit hard to follow, but it's a fairly high-level Sci-FI storyline about the creation of life. Surprisingly interesting and a not half bad delivery of what could be perceived as a dramatic ending. 8/10.
Graphics: Fortunately, the game doesn't launch in CGA resolution; that would be annoying. Rather, it fullscreened to my native resolution of 1080p without a hassle, so that's all good. As for the art direction, it's quite good, even if the MURI suits look a bit like Robo-Bunnies. Apart from that, the world designs are good, the enemy designs can be absolutely fantastic, with the boss of Stage 3 being the big standout. I can't quite speak for whether or not it rigidly conforms to the EGA palette or not, but it looks DOS-y and it looks good. 5/5.
Sound: This is something that I don't think I've done in the year or so since I started reviewing games (three months since I started publishing Steam reviews): I'm not gonna rate sound. I really can't, since the game itself goes for yet another factor of the DOS design in that there is no music - save for the title track - and all of the sounds are blips. So yeah, it feels a bit weird to do that, but that's what's happening.
Overall scores are: 10/8/5/0; 9.2/10. A very solid little shooter that's well worth the money. I'll definitely play it again in the future.