Suggestions
Really fun little time diversion, liked upgrades and medals. I noticed some missles and rockets would freeze mid air and just hang there(only happened after planes showed up). I would consider a rework of the grenade dropping system as they dont seem to be too effective, perhaps explode on contact or a longer timer as you could not get them to detonate on the ground if you are high up(as your guide suggests). Nice work.
Amusing
This game is pretty amusing. The controls are simple enough and I'm liking the design of the mecha used. As opposed to a land assault you opted for an aireal assault which I found pretty unique for a WASD movement game. Keep up the good work.
~Kev
Entertaining.
At first I thought that this game was going to end up boring me and I would quit a few minutes into starting it, but I was delighted to be proven wrong. I think it was the slow start to the game which made me feel like it was boring, but it quickly picked up with the introduction of new enemies and the numerous modifications you made available for your mech.
Another thing which grabbed my interest was the change in music as soon as you got a bit farther into the game (I think around where the vehicles show up) which introduced not so much a change of pace, but it certainly felt like one with the quicker and more upbeat tunes.
Some things you could work on, however, are probably the locations. People might enjoy this a bit more if it was side scrolling/backgrounds changed with each level. It would give some people that sense of moving that some people find necessary to make a game enjoyable for them and feel like it isn't very repetitive. Other than that you did a great job, congrats.
Great game.
Easy to play, and nicly done. Good job.