Just tested the game for a good hour! Here's my review:
PROS
Presentation
Very good use of your assets, not only in the game but also in the title screen. I was pleased to see a menu that actually works! My first steps in the game were very inviting and I felt compelled to play. A nice "Contra feel"!
Graphics
Bravo to the pixel artist, great job on the assets. I'm a professional pixel artist myself and it pleases me to see solid graphics. The characters are also cool and cute at the same time, colorful and easy to notice.
Music
Great track! Very engaging, goes well with the pace of the game. I would've wanted a different track for the main menu and the character death, but this is an alpha build, I'm sure this will come later.
Difficulty
That game is tough as nails haha! Just like a Contra-like should be. The duck mechanic doesn't quite make sense visually since bullets sort of go through the player when he uses it, but the mechanic itself works well and most of the time, if I die, I know that it's my fault!
CONS
Gameplay
I feel like a bunch of power-ups would help this game tremendously. A health pack, different weapons, etc. Something to break the monotony of the game's loop. Right now, it's a game that could get boring very quick for some crowds who are not necessarily looking for a super-tough gameplay with rigid mechanics.
Accessibility
The absence of checkpoints or health packs could make this game extremely hard for the regular crowd, therefore inaccessible. Not saying that it's a bad thing, but if your goal is to sell to a large audience, I think you guys are gonna need these features.
Visual Feedback
The game can get crowdy sometimes, some enemies could be more visible (like the turrets, for example). Maybe different types of colors or bullet shapes would help, a different color palette for some metallic textures, etc.
Bugs/Hindrances
A few bugs need to be corrected: - Crashes sometimes when jumping up through a bridge. - Bullets don't get their original range back if I hold the shoot button while killing an enemy. - The character can't move while aiming up / diagonally or crouching. Adding these features could help the player experience tremendously.