From Kirbypedia

Kirby's Dream Course features several objects found on the checkered course that can either assist or impede the player. Learning how to navigate these obstacles can mean the difference in a birdie or a hole in one.

Bumper:

These green edges line the courses, mostly, and keep the ball from rolling out of bounds. Kirby can bounce off from them or get an added boost with a well timed A button press.

Kick Panel:

An arrow within a blue circle complete alters the ball's course, no matter how fast it may be traveling. The player moves, at the same speed and bounce, along where the arrow is pointing.

Danger Zone:

These open, spiked pits are not safe to touch. Rolling into one takes off one tomato and tosses the injured Kirby out, but another one is taken if the ball falls back in before reaching safe ground.

Warp Panel:

These flashing squares will immediately change the ball's position on the course. They come in two varieties. A blue panels has an accompanying arrow and will reproduce the ball with that direction of travel. A red panel does change the course taken and tosses out the ball just as it was when entering the other side.

Pond:

This water filled recession can prove tricky to cross or get out of if sunk. It can be frozen into a rink with Freeze, rolled over with Wheel, or skipped over with a well timed boost from the A button.

Water Switch:

This button can control the fill of nearby ponds. A dimmed button lets the water in while a lit up button drains it out.

Turntable:

This tile rotates and can throw the ball off its laid out path of travel. It can be controlled with nearby switches.

Turntable Switch:

This button can stop or start the tile rotation. Pressing a lit, swirled face stops the motion while a dimmed circle starts them up.

Bunker:

This sand trap greatly reduces the ball's momentum. It is near impossible to roll through and is best traveled over through the air or with an ability.

Lawn:

This grassy field has its blades laying a particular direction, indicated with the white carrots. If the ball rolls into this patch, it gets pushed slowly in that direction.

Trampoline:

This elastic area has no effect if merely rolled over, but a jump shot or fall onto it springs the ball up with great force.

Conveyor Belt:

This stretch of track pulls a stopped ball along all the way until its end.

Air Curtain:

This vent jets a stream of air outward that can lift the ball off the ground.

Dash Panel:

This flashing series of arrows boosts the ball towards the direction pointed. It does not completely alter the path but adds momentum in that direction. The amount of acceleration gained depends on how long the ball has contact with the pad.

Day and Night Switch:

This sun and moon button can only be found in the 2-Player courses. It calls upon Mr. Shine and Mr. Bright to switch the star count between the two players. The panel can only be used three times on a hole before deactivating.