Megatroid is a game from Triolith Entertainment, who also brought us Wisp and Thunder Bang. It's a simple platforming shooter inspired by retro titles like Mega Man and Metroid, though the game didn't feel very Metroid to me without the exploration elements. It's a solid title with some really unique and experimental ideas, but it also isn't a very strong game overall. Still, for free, it's surely worth an hour or two of your time.
You play as Hali, a rebel fighting against the tyrannical machine empire that rules the galaxy, and you've got a little flying robot sidekick named S.P.A.K.K aka Self Propelled Ariel Kinematic Kitten. Gameplay includes your classic run, jump, and shoot, with Hali being able to take multiple hits before death. You can also wall-jump and do various other such tricks as you blast robots to oblivion and collect currency. You can take currency into the various in-game stores to buy better weapons and armor, and there are in-app purchase credits available as well.
While this is a nice little game that won't cost you anything to play, I can't rate it too highly. You see, there is no real level progression. Levels are randomly generated based on whatever world you've entered at the level warp gate based on some algorithm. This is really cool and impressive, but it robs the game of any real feeling of progression. You level up and get better guns, which unlock boss rooms and stronger enemies in each level, but it also feels very slow. However, even at level four I haven't unlocked the first boss room yet, and the random pieces they use to assemble the levels are starting to frequently repeat themselves. Maybe the idea is novel enough to make up for it, but without a hand-crafted and designed experience, it just feels totally random and pointless.
I don't mean to be too harsh. The game does look and sound quite nice, and the core gameplay is solid. It just takes too long to feel like you're really getting anywhere. But on the bright side, this game is truly trying something new, so the points it loses for sloppy progression it regains for innovation. The game is free after all. So what are you waiting for?