Differences and Similarities
All three parties have different political views as well as different views of the economy. The Communist Party wanted to overthrow the Republic and all of its institiutions. They also wanted everything to be distributed equally such as land. The Nazi Party wanted to create a new program where Jews were excluded from and did not want them to be apart of the nation. The Nazi Party only wanted only Germans in their country they did not want non citizens which left the immigrants to face the rules of Germany and a possibilitiy of being expelled from the country.The Social Demoncratic Party wanted to maintain the Republic. They also wanted to help the citizens of Germany by providing unemployment benefits for 6 months, lowering taxes and gave them rights to speak and write about issues without inerference. All three parties wanted to do what they thought would benefit the people of Germany.

Hitler's Final Speech at his Trial for Treason, March 27, 1924
The army that we are building grows from day to day, from hour to hour. Right at this moment I have the proud hope that once the hour strikes these wild troops will merge into battalions, battalions into regiments, regiments into divisions. I have hopes that the old cockade will be lifted from the dirt, that the old colors will be unfurled to flutter again, that expiation will come before the tribunal of God. Then from our bones and from our graves will speak the voice of the only tribunal which has the right to sit in justice over us.

My interpretation: Hitler was trying to build a strong army so that when the time comes he is prepared and ready. He wanted to revive the colors again and wanted people to believe in him and his ideas.