My isometric game looks flat; how can I improve this?

Being bored I decided to make my game isometric by applying a simple filter effect.

    g.scale(1f, 0.5f);
    g.rotate(400, c.getHeight() / 2, 45);

It works great, but now everything appears... flat.

Answer

Your technique could work, to some limited extent, but you don't want to apply the same transformations for the objects that are supposed to be standing. For these, make a simple "skew", as illustrated here: The second rotation might not be the inverse of the first as it depends on the scale factor. The important thing is that the vertical lines are actually vertical, i.e, aligned with the y axis (look at the dashed lines). Also, you might want to scale back a little. This is more important for doors than characters.

But still, as the commenters said, if this project goes beyond boredom avoid this method and begin making isometric art with a regular grid :)