The first act is pretty nice. I really like it in terms of gameplay (mostly). It was very balanced and there was enough challenge for a "first level". However, in the section where you snake around with the GFZ textures, It got a little repetitive. My only main problem is the graphics. It seems like they don't stick together very well, especially during the theme transition, or was there one? There are too many textures on this map that don't relate together. Pick a theme and stick to it. Also, I felt that a few areas, such as where the paths meet, were way too wide. The music remix is nice, although it should be used on the second act. That's just a personal preference though.
The second act wasn't so great. It felt too linear and where I thought I was going an alternate route, it ended up being me going around in circles. The map wasn't too narrow or too wide. However, many of the problems from the first act are also in the second. Once again, there were too many unrelated textures. You should also reduce the number of rocks in the areas that have them.
The boss stage was just a typical boss fight, but there are still some problems with it, too. Put an invisible FOF in front of the purple building to prevent going down the stairs. I fell down there thinking I was going to die, and it took me a while to get out. It's just annoying. Also, I noticed when I loaded up the boss stage, it looked just like Act 2. It's OK if you want to have the boss fight right where Act 2 ended, but you don't need to recreate the entire second Act just for that. Only recreate the sections that the player is going to see and it will help reduce lag (if any).
Overall, gameplay's okay, but graphics are severely lacking.
Overall Score (For Now): 6/10