I don't trust too much the IQP in an ending it is simply weak and  as black I usually wait until white has played Nbd2 or Na3 to take on d4

The black end up winning because they get to have a valuable piece on the centre which controls man places. It is also good because it will take a lot of moves to take it of there.

after d4 black will eventually have to exchange on d4 leaving white with a potentially dangerous IQP and a free c3 square for his knight

e5 seems like a bad version of the french as the bishop will go out of the pawn chain I'd probably play Nc6  Bf5(g4) and e6 and black can fight for something more than equality

I presume that you mean 1.e4 c5 2.c3 d5 3.e5  

The move is playable, and it leads to positions that might resemble the advance variation of the Caro-Kann. 

There are only about 35 games in the chess.com database with 3.e5 and few if any where both players were 2400+.     This doesn't necessarily mean the move is bad, however it does mean that 3.e5 isn't very fashionable.

why can't you advance the E pawn instead of taking D5?

but the knight is blocked 

from one side

it dosen't look like a good opening

after c4 white must be much worse.

d4 is simply too weak after Qd6 and e5 followed by Nc6 Nge7 trying Nf5 and Nd4.if black can stop any attemp of white to get activity black should be better.

White can move his c-Pawn with 4.c4 however that gets back to my earlier remarks.  It wastes an important tempo.  Not only that, the vital d4 square is now weakened and could well be a liability.  

I'd say the move is playable, but it's no advantage at all, and might leave White a little worse.

Here's an example:   4.c4 Qe4+ 5.Qe2 Qxe2+ 6.Bxe2 Nc6 and White has to be thinking about how to equalize.

What about c3-c4.

As Black, you should not miss any opportunity to get in an early ...e5.  In fact, it is because of this that White is virtually forced to play 4.d4 and isolate his d Pawn.  If White omits 4.d4 you can often achieve a Maroczy bind structure, which will usually offer equality with good chances.

If you want to play this with white, you should check out how to play with an isolated d4 pawn. Having an isolated d4 pawn with white has its good and bad sides. So check out some games and maybe even find books on this very exciting topic. It is important here, because white will play d2-d4, Ng1-f3, Bc1-e3 and support the d4-pawn while black can give white the isolated pawn with cxd4 at some point. You will notice that if you keep the queen and the light squared bishop, that d4 pawn will help you attack black's king. If you on the other hand exchange many pieces and go into an endgame that d4 pawn can be a disaster. Thanks for reading and good luck.

d4

This is a good way to meet the Alapin.

The "point" of Black's play is that White has no immediate move to drive the Queen away without wasting a tempo. The Pawn on c3 prevents a Knight from going there immediately.  White often ends up moving his c Pawn a second time.

Horrid, I'm at a loss of words.

bad

if you're white

;)

dont like this for white because u are forced to play Nf3

good