Sniper is a very straightforward hard carry with the longest auto-attack range in the game. If it is properly utilized Sniper becomes an extremely irritating and deadly adversary. That said, Sniper is also extremely squishy and can be countered easily by high level opponents, so I only recommend playing him in public matches.
+Best range in the game
+Passive mini-stun interrupts/irritates enemies
+Assassinate has long range and huge damage
+Hard to beat late game if fed
+Easy to last hit creeps
-Squishy Squishy Squishy
-One of the slower move speeds
-Easily countered by good players
-Many people will get mad if you pick him
As Sniper, you ABSOLUTELY MUST utilize his range to the fullest potential whenever possible. This means staying as close as your tower as possible Doing so means you avoid most harassment while you are able to harass your enemy and still land your last hits. Because his range is so important, max take aim ASAP.
Using his range to harass the enemy mid, you can punish them for trying to get last hits and still get in last hits and denies. With a couple lucky mini-stuns (extra damage) you may get the enemy health low (around 25%) JUMP ON THIS CHANCE IMMEDIATELY use your ultimate (assassinate) with monster range and damage and you will most likely secure your first kill.
AVOID AVOID AVOID
You want to be in the back of the team fights ALWAYS. Your range allows you to peck at enemies without them realizing and before they even notice you're shooting at them they're low enough for you to Assassinate them in the face.
Keep in mind you are SQUISHY, let your teammates distract the enemy. If you even get the feeling someones going to put the hurtin on you, pop your SHADOW BLADE and head for the nearest tower or back to base.
If you manage to escape a few hairy situations with your Shadow Blade, also keep in mind your enemies might buy DUST OF APPEARANCE to counter your ***.
If this happens play safe, and stay with your teammates
If you managed to get a good amount of kills/farm the endgame should be straightforward. Your Desolater/Daedalus combo should tear any hero a new ******* just by auto attacking.
One critical from this combo should do more than a MAXED ASSASSINATE
Sniper can be a very deadly hero if played correctly however there are also many many counters to him and he can be easily killed.
Things to especially avoid
-Basically everything that does damage
Bad news heroes for Sniper
There are so many heroes that can screw over a sniper, in fact too many to say, but I will name a few that cause you the most problems:
The list goes on and on, which, in part, is the reason so many people hate on snipers. Anyone with a stun could mean the end for sniper but again, utilizing his range will mitigate most damage.
Sniper is an extremely easy hero to play and is geared towards newer players. Things to remember when playing sniper:
RANGE RANGE RANGE
SNIPE LOW HP TARGETS
AVOID DAMAGE AT ALL COSTS
Do these things correctly, and you should be one of the top scorers on your team. Happy Sniping!