I hope you didn't use Fruity Limiter in the Master Channel, that's a no no.
You're better off using Maximus, but don't use any of the presets. It'll take a while to figure out a good combination of settings, but it really boosts the overall mix if used correctly.
1:55 sounds really weird to me. Out of place even. The song is too busy at this point.
At 2:56, the lead moves around too much, and goes into the highs a fair bit, hurting my ears. The kick is also too loud at this point, it's starting to distort.
You also told me you use samples, and I've said before, your better off learning some VSTi's, and just use VEC samples for rhythm/FX/etc. Synth samples are not only unoriginal, but not very useful either.
Overall, the mix is quite poor, there's a fair bit of bass distortion with the kick and bass. That may be caused by Limiter, I can't tell though.
Keep at it man, this song has potential, as B0UNC3 said.