I tried out Worst Space Guy. I cleared all three planets on normal mode then died on the fourth level of arena mode. Here's my thoughts:

-- The game seems like a bullet-hell shooter with orbital movement around a planet. That's a good premise, but I felt like the player's spaceship was both too wide (too hard to fit between oncoming bullets) and slightly too slow. It felt like there was a lot of time to see the bullets coming and prepare for them, although the width of the ship did make that a bit more difficult. A little more up / down range (i.e., the player could get further away from the planet) would also be good.

-- The planetary defense could fire through the planet itself. Not necessarily a bad thing, but it was unexpected. 

-- The planets all start out with all guns blazing, and the levels get easier as you pick them off one by one. Things got less exciting (and less fun) as you went through a level. I think it would be more exciting / tense / dramatic if planets had stages of defense. Once you clear the first layer (shields or whatever), more turrets appear and the stakes are raised.  You could do other things, of course, but I feel this area (raising tensions) would be were the most interesting design work could happen.

-- Another idea would be including powerups from downed turrets. This could help introduce variety into the player's strategy.

Not a bad start to a game. I think increasing the pace and increasing the player's maneuverability are the first things to do, and then see where it goes from there.