I think the devs made many mistakes. The biggest mistake are the visuals. Ok, its a damn wonderful game, with nice effects good abstract levels many very neat looking ships, many fiend models and so on. But the fact that on most points this game is running with 10fps is fucking unbelieveable and totally not acceptable. I mean for sure one tester was pointing out that at times this game getting to damn slow that u wish to can sleep during such periodes. I dont know why Irem still packed it up with background polygons and textures (which are super nice but in this case gameplay destroying). In the first stage there are times when you have 10 seconds nothing on the screen to destroy. Which leads my straight to the level design.
Iam quite sure, they did employee more visual artists then gameplay designer because if Iam looking back to old days (R-Type Delta) the levels where packed full of enemys with memorable stages and the learning curve (except Stage 6 and Final) were good balanced. Nowadays it seems that the devs forgot to but in some enemies because even in Stage 5 or FA there are periods were you can be inactive for about 5-10 secs which is too much.
And why on earth did they develope a system where you have to spend playtime to get another ships. I hate them for doing this because who spends 2 damn hours with one ship to get another. Ok I wouldnt have a problem if the level design where good like in R-Type 3 or Detla where time is getting liquid as you move through the stages, but who gets bored the second time he flew through this damn Stage 3 in Final ?
Thanks to cracks (or maybe the devs itself) for getting us the little trick in Stage 3 where you can spend 3 hours with a ship without have to care about your Ps2. This is the only points which motivates me to get more ships.
Why not implement things such: Destroy boss 2 in Stage 2.2 with a Beam Shot to get the next ship or dock and undock your satelitte on your ship 20 times. Ok not the best ideas yet, but far more funny then flying 90 minutes with a ship which got noting better as a Beam shot then a sword (shitty Hakusan

Ok enough of the bad, there are of course good things in it, thats why I spent over 50 hours with it. The level variants are pretty cool, especially Stage 2 and F ( I though would like to see more Stages if Iam forced to play with it more than 50 hours ). The ships are pretty cool, some of them are very useless, and it seems that Irem just tried to make quantity not quality, but most of them offers special gameplay experiences. The music is that awesome, e.g Continue or Stage 2.3-2.4.
What do you think about R-Type Final, does Final justify the slowdowns, the system or 101 ships ?
Thx for slateman for his great ship list
http://www.slateman.net