Finished my first playthrough today - a little over 6 hours and a little under 70%. I really enjoyed it though I found some of the enemies near the end a bit annoying (the ones whose bullets push you back).
Overall, I found the levels to be a bit too sprawling. By time I got to the end level, I just didn't feel like running back through the other zones to collect everything, however I did enjoy looking around as much as possible when ever the game led me through the various areas.
I didn't read anything going in and unfortunately played it on Normal. By and large the game was far too easy on this difficulty level and while I look forward to trying on hard, I am going to miss having the same degree of mobility (for the first bit anyway). With that said, combat is fast and fluid, but I feel like it could have benefited from being a bit deeper - Strider has a lot of options, but by and large I felt that the game could have used a lot more interesting enemies. I also did not like having to use the dpad to change plasmas as it was a bit cumbersome (though I don't have good solutions to these issues). If this had been implemented differently, I think there would have been more options for using different plasmas dynamically in the various encounters. As it is, I tended to only use one plasma once I had engaged the enemy and maybe switched if a different shield was present.
My only real complaint, is how horrid the voice acting was. I don't know if they just had the staff do it, or if they brought some people in off the street and fed them lunch, but it was atrocious. I tried to take it, but ended up having to turn the dialogue off.